Suibhne has been translated into many variations, i.e. Sween, MacSween, MacQueen, MacEwen in Scotlapd and Swiney, MacSwiney, Mac Sweeney, MacSwyny, MacSweyne and others in Ireland. In addition the armorial bearings of this Clan's Septs and Chieftain's altered considerably through the centuries maintaining throughout, however, the basic charges of boar and battle-axe.

The original and undifferenced arms are not historically verified, although they have been blazoned by Burke in his General Armoury as Or (or argent) three boars passant sable. A seal was used by the Lords of Knapdale in the 13th century, but no copy of this is extant.

The first officially recorded arms were borne by one Murragh Mac Sweeney, whose entry in the Annals of the Four Masters reads:
Murragh Mac Sweeney was taken prisoner in Umailia by Donnell, son of Manus O'Conor, who delivered him up to the Earl (de Burgh, Earl of Ulster) in whose prison he died.
This is dated The Age of Christ 1267. His arms are recorded as follows: Mac Sweeney (Co. Donegal). Moragh Mac Sweeney, Chieftain 1267, Reg.Ulster's Office. Argent a lion in Chief and a boar in base both pass. gules.

This lion charge is unusual and is repeated as we shall see in the arms borne by the Rt. Hon. Peter Paul MacSwiney, Lord Mayor of Dublin, who used this shield as a basis for the design of his Grant. This Morrogh had a colourful history, and the family annals mention him as "champion of the King of Scotland," which might account for the "ruddy" lion.

From another branch of this Clan, one john de Sweyne was Captain of the Cinque Ports Fleet of Edward I, and his father had close connections with Durham from whence the Balliols and Comyns had lands. john is also listed as having lands there, and many years later, during a Visitation by William Flowery, Norroy King of Arms (1575) a monument with the following arms was recorded: SWYNE: Argent a boar sable bristled or. (Note that this is virtually identical with Morrogh, without the lion in chief.)

Following the Battle of Bannockburn (1314) the Chief and senior line of the family established at Rathmullan Castle in Tyreconnell (present Donegal). This Chief's arms are recorded in Dublin Castle as: Or, a fess vert charged with a reptile argent between three boars passant sable. The similarity between these arms and the ones previously mentioned by Burke as the "undifferenced" arms may be noted. The addition of the green fess and white reptile is interesting. My only thought on this is that these Lords of Fanad introduced the Carmelites into Donegal and built a Priory for them at Rathmullan. As I recall one of the symbols of the Virgin Mary is a white chameleon...could this be relevant?

The crest of the senior line comprehended that of the Clan Neil, An arm in armour embowed holding a battle-axe proper. This also seems strange except for a tradition that the Clan Sween is descended from the Clan Neil. However in Ireland they supported the O'Donnell, for long the bitter enemies of the O'Neils.

Two Cadet Septs of the senior House quickly spread into other portions of O'Donnell's principality-that of na d'Tuath (or na Doe as the English translated it) at Doe Castle near Creeslough; and the Banagh branch at Rathain Castle on the western coast. These two septs adopted shields of similar design, though different tinctures:

Na d'Tuatha: Azure, two boars rampant combattant or, in chief two battle-axes in saltire of the second.

Banagh: Or, two boars rampant combattant sable, on a chief of the second two battle-axes in saltire of the first.

The crest of the former is A demi-griffin or, holding in its dexter claw a reptile vert. The crest of the latter is A boar passant sable.

It is difficult to know why these two Houses changed the design, except that the Mac Sweeney became known as "the Clan of the Battle-Axe," and they may have wanted this charge to figure more prominently on their shields. The designation came through two causes: The Battle-axe was the clan's "tool of it's trade" as galloglass warriors (see the author's "The Galloglass," The Augustan, X, vi, 261) and the designation na d'Tuatha was the districts) was easily confused with na d'Tuatha (of the district) was easily confused with na d'Tua (of the battle-axe) Another thought is that a Chieftain of na Tuatha was knighted in the reign of Queen Elizabeth I, and this altered design may have been instituted at that time.

A branch of the House of Tuatha went to the south where they became High Constables to the McCarthy Mór of Desmond, the most prominent branch centering at Mashanaglass Castle. This branch has continued a differenced version of the Tuatha arms: Per Pale gules and azure, each charged with a boar rampant combattant counter-ermine; on a chief or two battle-axes in saltire argent. The crest is A demi-griffin or charged with a fleur-de-lis sable holding in its dexter claw a reptile vert.

It is obvious that the tincturing of the chief violates the laws of heraldry. As a representative of this line was created a hereditary Roman Marquis, and the colours of the Vatican also violate the same rule (as did the Kingdom of Jerusalem) some reason for this might be sought therein.

Prior mention has been made to Peter Paul MacSwiney, the Lord Mayor of Dublin. His arms were obviously based on those of the ancient Morrough, and are Argent, a fess azure charged with two battle-axes in saltire Or between in chief a lion passant gules, and in base a boar passant sable. Here he has brought in every charge known to the family except the reptile, which he includes in the crest: A demi-griffin or, holding in its dexter claw'a reptile vert. Then to make sure he charged the griffin with Crossed battle-axes sable.

A branch of the House of Banagh became High Constables to the O'Conor Don, and to the Butlers, Earls of Ormonde. From this latter the armigerous branch descends who settled on Prince Edward Island, now a Province of Canada. Their arms follow the senior House of Fanad in tincture, although the bend vert has been replaced by two flaunches vert charged with antique crowns representing the ancient Gaellic kingdoms of Ireland and Scotland. For a crest they use a griffin vert, holding a battle-axe (from the Fanad arms again) and the reptile has disappeared. These arms can be blazoned Or, three boars in pale passant sable langued guess, between two {launches vert each charged with an ancient crown of the first. The crest is A demi-griffin vert grasping in its dexter claw a battle-axe proper and Motto: Clann na d'Tua Abu.

Thus arms change through the centuries even in the same family, yet remain similar enough to trace their development. Some of the reasons here given are based on the laws of probability and other hypotheses would be most welcome.

The description of the arms illustrated herein are as follows:

Sween of Knapdale: Or, three boars passant sable.

Mac Sweeney Fanad: Or, on a fess vert between three boars passant sable, a lizard argent.

Mac Sweeney Banagh: (Tuath) Or, two boars rampant combattant sable, on a chief of the second two battle-axes in saltire of the first.

Moragh Mór Mac Sweeney (1267): Argent, a lion in chief and a boar in base both passantgules.

Mac Sweeney na d'Tuatha (also Captain Daniel Gorm Mac Sweeney of Donegal, 1638): Azure, two boars rampant combattant or, in chief two battle-axes in saltire of the last (or).
Crest: A demi-griffin rampant or holding in the claw a Lizard proper.
MacSwiney of Mashanaglass: Per pale azure and gules charged with two boars counter-ermine, rampant combattant; on a chief or two battle-axes in saltire argent.

Crest (right): A demi-griffin rampant or holding in its dexter claw a lizard proper, and charged with a fleur-de-lis sable. Surmounted by a coronet of a Marquis.

Peter Paul MacSwiney: Argent on a fess azure between in chief a lion passant gules and in base a boar passant sable, two battle- axes in saltire or.
Crest: A demi-griffin segreant or, holding a lizard proper, and charged on the breast with two battle- axes in saltire sable. Motto:. Tuagha tulaig abu.

Sweeney of Bolger's Park Canada: Or, three boars sable, langued gules, in pale passant between two flaunches vert each charged with an antique crown of the first.
Crest: A demi-griffin vert holding in its dexter claw a battle- axe proper. Motto: Clann na d'Tua Abu.

The arms illustrated for the Bishop of Kilmore (above) and the Archbishop of Toronto (below) are those of their respective Diocese.

Bishop Sweeney of St. John chose as his shield a portrayal of the Virgin, with a halo of sever stars. (below)

Quarterly, 1 and 4: Or, three boars passant in pate sable langued gules between two flaunches vert, each charged with an antique crown of the lst, within a borduregules; 2 and 3, quarterly 1 and 4, Argent, six estoilles gules 2 and 3, Gules, a lion rampant or (for Mingo).

Crest: A demi-griffin vert holding in its dexter claw a battle-axe proper.

Motto: Clann na d'Tua Abu. Mantling: Gules turned argent.

Wreath: Or and sable. Badge: Two battle-axes in saltire proper within an ancient crown.
The whole surrounded by the Knight's Cross of the Military and Hospitaller Order of St. Lazarus of Jerusalem.